Uptake and translocation of non-ionised pesticides in the emergent aquatic plant parrot feather Myriophyllum aquaticum     

de Carvalho RF  Bromilow RH  Greenwood R 《Pest management science》2007,63(8):798-802

The uptake of four (14)C-labelled non-ionised compounds, the methyl carbamoyloxime insecticide/nematicide oxamyl and three model phenylureas, from solution by rooted stems of the aquatic plant parrot feather [Myriophyllum aquaticum (Vell.) Verdc], together with translocation to the emergent shoots, was measured over periods of 24 and 48 h. Uptake into the submerged tissues of roots and stem base could be ascribed to two processes: movement into the aqueous phase of cells and then partitioning onto the plant solids. This latter process was related to lipophilicity (as measured by the l-octanol/water partition coefficient, K(ow)) and gave rise to high uptake rates of the most lipophilic compounds. Translocation to shoots was passive and was optimal at log K(ow) approximately 1.8, at which the efficiency of translocation of compound was about 40% of that of water. This optimum log K(ow) was identical to that observed previously in barley, although the translocation efficiency was somewhat less in parrot feather. Solvation parameters were applied to model uptake and translocation of a set of ten compounds by barley with the particular objective of understanding why translocation efficiency is lower at log K(ow) > 1.8.  相似文献   

Quantification and persistence of recombinant DNA of Roundup Ready corn and soybean in rotation     

Lerat S  Gulden RH  Hart MM  Powell JR  England LS  Pauls KP  Swanton CJ  Klironomos JN  Trevors JT 《Journal of agricultural and food chemistry》2007,55(25):10226-10231

The presence of the recombinant cp4 epsps gene from Roundup Ready (RR) corn and RR soybean was quantified using real-time PCR in soil samples from a field experiment growing RR and conventional corn and soybean in rotation. RR corn and RR soybean cp4 epsps persisted in soil for up to 1 year after seeding. The concentration of recombinant DNA in soil peaked in July and August in RR corn and RR soybean plots, respectively. A small fraction of soil samples from plots seeded with conventional crops contained recombinant DNA, suggesting transgene dispersal by means of natural process or agricultural practices. This research will aid in the understanding of the persistence of recombinant DNA in agricultural cropping systems.  相似文献   

THE NEW VAPOR-ENGINES     

Thurston RH 《Science (New York, N.Y.)》1902,15(375):379-382

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BRYAN DONKIN     

T RH 《Science (New York, N.Y.)》1902,15(378):515-516

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免耕大麦田甲黄隆应用技术研究     

范文海  鲁学高 《嘉兴农业》1993,(1):49-50,25

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观赏植物的病害防治现状——植物病毒学     

Laws.  RH 龚明熙 《广东园林》1996,(2):41-47

1、前言2、免疫学检测3、抗血清制备4、测试方法5、用于诊断的血清学商品试剂来源6、核酸检测7、观赏植物中4种病毒的检测方法灵敏性的比较8、病毒传播介体的防治9、植物保护10、组织培养在无毒苗木生产上的应用11、寄主抗性  相似文献   

Ochratoxin A on green coffee: influence of harvest and drying processing procedures     

Paulino De Moraes MH  Luchese RH 《Journal of agricultural and food chemistry》2003,51(19):5824-5828

Ochratoxin A is a metabolite produced by Aspergillus and Penicillium species that is nephrotoxic and possibly carcinogenic to humans. The aim of this study was to evaluate ochratoxin A contamination in green coffee obtained by different harvesting and drying operations and from fruits of different ripening stages in order to identify hazards. The research was directed to coffees from the highland area of Rio de Janeiro state (Brazil), which is traded in the domestic market. Twenty-two out of 54 samples contained ochratoxin A at levels ranging from 0.3 to 160 microg/kg. Ochatoxin A contamination levels between different ripe stage fruits were not significant (P > 0.05). "Varri??o" coffee, consisting of fruits that fell from the tree spontaneously and stayed longer on the ground before being harvested, was the most contaminated. Eleven out of 14 samples of varri??o coffee were contaminated. Three out of 10 samples from the northwestern region of the state were positive for ochratoxin at levels ranging from 10.1 to 592 microg/kg. The contaminated samples had in common the fact that they were harvested directly from the soil.  相似文献   

Quantitation of transgenic plant DNA in leachate water: real-time polymerase chain reaction analysis     

Gulden RH  Lerat S  Hart MM  Powell JR  Trevors JT  Pauls KP  Klironomos JN  Swanton CJ 《Journal of agricultural and food chemistry》2005,53(15):5858-5865

Roundup Ready (RR) genetically modified (GM) corn and soybean comprise a large portion of the annual planted acreage of GM crops. Plant growth and subsequent plant decomposition introduce the recombinant DNA (rDNA) into the soil environment, where its fate has not been completely researched. Little is known of the temporal and spatial distribution of plant-derived rDNA in the soil environment and in situ transport of plant DNA by leachate water has not been studied before. The objectives of this study were to determine whether sufficient quantities of plant rDNA were released by roots during growth and early decomposition to be detected in water collected after percolating through a soil profile and to determine the influence of temperature on DNA persistence in the leachate water. Individual plants of RR corn and RR soybean were grown in modified cylinders in a growth room, and the cylinders were flushed with rain water weekly. Immediately after collection, the leachate was subjected to DNA purification followed by rDNA quantification using real-time Polymerase Chain Reaction (PCR) analysis. To test the effects of temperature on plant DNA persistence in leachate water, water samples were spiked with known quantities of RR soybean or RR corn genomic DNA and DNA persistence was examined at 5, 15, and 25 degrees C. Differences in the amounts and temporal distributions of root-derived rDNA were observed between corn and soybean plants. The results suggest that rainfall events may distribute plant DNA throughout the soil and into leachate water. Half-lives of plant DNA in leachate water ranged from 1.2 to 26.7 h, and persistence was greater at colder temperatures (5 and 15 degrees C).  相似文献   

Potential cell culture models for antioxidant research     

Liu RH  Finley J 《Journal of agricultural and food chemistry》2005,53(10):4311-4314

The antioxidant activity of pure compounds, foods, and dietary supplements has been extensively studied with the development of many new antioxidant and antioxidant activity assays in recent years. However, these assays, such as total phenolics, total flavonoids, and total antioxidant activity in vitro, do not reflect the cellular physiological conditions and do not consider the bioavailability and metabolism issues. In addition, the mechanisms of action of antioxidants go beyond the antioxidant activity scavenging free radicals in disease prevention and health promotion. Animal models and human studies are expensive and not suitable for initial antioxidant screening of foods and dietary supplements. Therefore, there is a need for cell culture models to access the bioactivity of antioxidants. This paper is an overview of cell culture models for antioxidant research, as reported at the First International Congress on Antioxidant Methods, held in Orlando, FL, June 16-18, 2004, and outlines potential cell culture models for initial antioxidant screening and antioxidant research.  相似文献   

FUM13 encodes a short chain dehydrogenase/reductase required for C-3 carbonyl reduction during fumonisin biosynthesis in Gibberella moniliformis   总被引：1，自引：0，他引：1  

Butchko RA  Plattner RD  Proctor RH 《Journal of agricultural and food chemistry》2003,51(10):3000-3006

Fumonisins are polyketide-derived mycotoxins produced by the filamentous fungus Gibberella moniliformis (anamorph Fusarium verticillioides). Wild-type strains of the fungus produce predominantly four B-series fumonisins, designated FB(1), FB(2), FB(3), and FB(4). Recently, a cluster of 15 putative fumonisin biosynthetic genes (FUM) was described in G. moniliformis. We have now conducted a functional analysis of FUM13, a gene in the cluster that is predicted by amino acid sequence similarity to encode a short chain dehydrogenase/reductase (SDR). Mass spectrometric analysis of metabolites from FUM13 deletion mutants revealed that they produce approximately 10% of wild-type levels of B-series fumonisins as well as two previously uncharacterized compounds. NMR analysis revealed that the new compounds are similar in structure to FB(3) and FB(4) but that they have a carbonyl function rather than a hydroxyl function at carbon atom 3 (C-3). These results indicate that the FUM13 protein catalyzes the reduction of the C-3 carbonyl to a hydroxyl group and are the first biochemical evidence directly linking a FUM gene to a specific reaction during fumonisin biosynthesis. The production of low levels of FB(1), FB(2), FB(3), and FB(4), which have a C-3 hydroxyl, by the FUM13 mutants suggests that G. moniliformis has an additional C-3 carbonyl reductase activity but that this enzyme functions less efficiently than the FUM13 protein.  相似文献